1. Field of the Invention
The present invention relates to a crushing apparatus for waste material that comprises a drive, a housing having a filling opening, and a rotary crushing drum which has peripheral cutting bars and which cooperates as a counterpart cutting tool.
2. State of the Prior Art
A crushing apparatus of the kind in which a counterpart cutting tool is a stationary counterpart blade is known, for example, from DE-U-91 09 063. In order to prevent intermediate spaces between the cutting elements of the tool from filling with material, the apparatus has a clearing spatula member which, when coupled to a drum drive of the apparatus, continuously engages with respective intermediate spaces and cleans out the spaces.
Crushing apparatuses in which a counterpart cutting tool is formed by a crushing drum are also already know. The crushing drum can be formed from crushing disks that are fitted with canine teeth and that are arranged with a spacing relative to each other on drive shafts. It is, however, also possible to use one-piece crushing drums on which cutting elements or teeth are provided in axially spaced relationship. Examples of both constructions are to be found in AT-B-350 988.
A problem in all waste crushers or grinders is that the waster materials which are to be reduced in size are of different properties so that the crushing apparatuses are only more or less satisfactory in function. It repeatedly happens that, in spite of a possible reversal of the drive, and in spite of clearing elements which engage with the intermediate spaces, the material is poorly crushed or reduced in size, and becomes jammed. The apparatus must then be at least partially dismantled to clean it out.
FR-A 753.030 describes a kneading mill for swollen corn, FR-A 497.045 describes a device for shredding a field crop, and FR-A 2466 281 describes a device for producing small pieces of tomato pulp. Each of the three devices comprises screening drums provided with bars which engage one another and have to strain a material, which then exits the ends of the screening drums. Passage of the material between the screening drums is not possible, because the housing below the drums is closed.